Various means have been used in the prior art to provide a safe pressure vessel for quick, safe storage for improvised explosive devices. Some prior art devices use a bolted closure, such as a flat plate, to seal an access port of the vessel. The difficulty with the use of this device was the inordinate length of time necessary to effect a closure and the lack of adequate strength to contain the detonation products therein. Other prior art devices use an internally hinged flat plate door, which is larger than the vessel's access port, to effect a closure. This type of closure is operated by swinging the door into the vessel's interior. Other prior art devices use cafe style doors which are similar to the internally hinged door with the exception that the door is cut vertically in half and hinged on both sides of the port inside the pressure vessel. A further type of door used on prior art devices had pressure cooker type closures. The pressure type closure generally uses an interrupted ring lock with an inclined plane for locking. This latter type of closure is frequently operated by inserting the door into a breach on the vessel and rotating the cover a few degrees to lock the lugs on the cover against the lugs on the vessel. The problem with the aforementioned prior art devices included interference with the internal configuration of the vessel or the contents contained therein, lack of complete sealing of the detonation products, difficulty or length of time required to operate the closure, and lack of adequate strength to contain the products of the explosive device.